Hot die casting molding is also known as hot pressing injection molding, the so-called hot pressing injection molding method, is under the action of pressure, the molten wax containing slurry (wax slurry) is filled with metal mold, and in the mold after cooling and solidification, and then demoulding.
Introduction to the
Also known as hot pressing molding, is one of the most intensively in the production of special ceramics a production process, its basic principle is to use the paraffin wax heating melting and solidification characteristics, get cooler are plastic desert ceramic powder and hot wax liquid mixing to form the flow of slurry, metal mold injection molding under certain pressure, cooling after being wax slurry solidifying patterns take shape good body. The blank body is properly trimmed, buried in the adsorbent and heated for dewaxing treatment, and then the dewaxed blank body is fired into the final product.
The products formed by this method are accurate in size, high in finish and compact in structure, and have been widely used in manufacturing industrial ceramic products. Some ceramic daily necessities are trying hot pressing molding, and there have been hot pressing molding production lines in foreign countries. Hot pressing molding is becoming one of the new methods for the development of daily porcelain molding.The hot press injection machine used in the hot press injection process is a pressure air type hot press injection machine which pressurizes the wax slurry with compressed air. The wax slurry is sent into the injection mold by using a constant temperature closed slurry bucket and compressed air. Before forming, put the wax slurry into the slurry bucket, and electrically heat the wax slurry to reach the required temperature.
Outside the slurry bucket is the oil bath bucket to maintain a constant temperature. The node thermometer is inserted into the bucket, and the relay is connected to control the temperature. When forming, the slurry inlet of the mold is aligned with the slurry outlet of the injection machine, the valve of the compressor is stepped, and the top rod of the slurry pressing device is pressed to the mold. At the same time, the compressed air enters the slurry bucket and the slurry is pressed into the mold. After maintaining for a short time, stop the slurry and discharge the compressed air. Open the mold, take out the hardened blank body, cut the grouting mouth with a knife, and get qualified blank after dressing.
The powder used is dry powder. Its CAN USE THE WASTE OF PORCELAIN FACTORY DIRECTLY — THE PORCELAIN THAT BREAKS OFF, ALSO CAN USE MINE MATERIAL TO MAKE UP OF COURSE. If the ore material is used to prepare, it needs to be pre-fired. When pre-fired, the billet is made into particles and pre-fired to the sintering temperature of the material in the sagger, and then ground into powder. The fineness of powder also needs to be controlled.
Generally speaking, the finer the powder is, the larger the surface is, the more paraffin wax is needed, and the viscosity of fine particles and wax slurry is also large, which is not conducive to pouring. If the particle is too large, the wax slurry is easy to precipitate unstable. Therefore, for the powder, it is best to have a certain particle grading, in the process of general control of the sieve of ten thousand holes is not more than 5%, and all through the sieve of 0, 2mm aperture.
It is proved that if the size of large particles can be further reduced to less than 60um, and the fine particles of 1~2um can be reduced as far as possible, the wax slurry and product with good performance can be made. In addition, the water content of powder should be controlled below 0, 2%. The wax slurry with too much water viscosity, even can not be adjusted into uniform slurry. The powder is baked in an oven at 60 to 80 degrees before mixing with paraffin.
Within a certain temperature range (such as 60~90 degrees), the slurry temperature rises and the slurry viscosity decreases, which can make the billet particles compact and reduce the shrinkage hole in the billet. If the slurry temperature is too high, the billet volume shrinkage increases, the surface is prone to pit. Slurry and billet body size, shape, thickness. The shape of complex, large, thin wall body to use a higher temperature of the slurry to press injection, general slurry temperature control between 65~80 degrees.